1. Field of the Invention
The present inventions relates to an image processing apparatus, image capturing apparatus, image processing method and image processing program, and in particular to a technique for storing a best shot image.
2. Description of the Related Art
A face image processing method has been proposed in the prior art. The method includes continuously inputting a human image including a face image, judging a state of a subject's face (e.g. a state of the pupils) from the image, and automatically selecting an image including a suitable face image which matches the desires of the user (Japanese Patent Application Laid-Open No. 2000-259833). This method makes it possible to obtain, for example, an image which includes a suitable face image in which the subject has their eyes open by pointing the camera at the subject for a certain length of time.
An image processing apparatus has also been proposed in the prior art. The proposed image processing apparatus finds characteristic points in predetermined parts (corresponding to the eyes, mouth and nose) in a face contained in an inputted image, and finds characteristic amounts for the predetermined parts (e.g. the distance between an end point of an eye (characteristic point) and an end point of the mouth (characteristic point)). The image processing apparatus also finds characteristic amounts for the predetermined parts in another image containing a face of a predetermined facial expression. The image processing apparatus further calculates differences for each predetermined part between the characteristic amounts of the inputted image and the characteristic amounts of the other image, and calculates scores for each predetermined part based on the differences. By comparing a distribution of the scores calculated for the inputted image with known distributions of scores calculated for the predetermined parts in faces of various facial expressions, the image processing apparatus judges which facial expression is on the face in the inputted image (Japanese Patent Application Laid-Open No. 2005-56388).
Further, according to the image capturing apparatus of Japanese Patent Application Laid-Open No. 2005-56388, when a user wishes to capture an image including a desired facial expression (such as a smile), time-series images including the face are captured, and the distributions of scores calculated for each of the images with a distribution of calculated scores for predetermined parts in a smiling face are compared. By storing only the image having the distribution closest to the distribution for the smiling face, the image capture device is able to store an image including the desired expression.